Support updating SDK key at runtime - ideally using Microsoft.Extensions.Options primitives

[flakey-bit]

Is your feature request related to a problem? Please describe.
We share our SDK key for a LD project among many components that are deployed.

We would like to be able to easily rotate the SDK key without having to recycle all of those components (across many teams in our organisation!)

Describe the solution you'd like
We're aware that the Launch Darkly SDK goes to some lengths to ensure low latency when calling code evaluates flags.

So ideally, we'd like to stick with a single LD client registered in the IoC container (singleton, as recommended by LD).

However, we would like the client to automatically notice when the SDK key has been updated and seamlessly start using the new key.

The Microsoft.Extensions.Options primitives - in particular IOptionsMonitor would be a good/natural fit for this.

Describe alternatives you've considered
Trying to coordinate recycling of components across multiple teams. We're aware that when a key is rotated, the old key can be kept functional for up to 30 days.

Additional context
N/A

[kinyoklion]

Hello @flakey-bit,

Thank you for the report. We will consider the request and look into options.

The SDK currently isn't designed to allow for runtime changes of any configuration, and changing configuration will likely be similar in performance to initializing a new client instance. Likely equal to a wrapper around the client that detects changing and then initializes a new internal client for the singleton to use.

Thank you,
Ryan

Filed internally as SDK-1571